The goal of this project is to define the regulatory events involved in the expansion of the protein synthetic apparatus in the mosquito fat body accompanying synthesis of yolk protein, or vitellogenin. Since the ribosome is the most abundant component of the protein synthetic appratus, these studies will focus on the synthesis and degradation of ribosomes during the vitellogenic cycle. Complementary studies will be done in mosquito fat body, in which vitellogenin synthesis is under precise hormonal control, and in cultured cells, which provide a convenient and well-characterized system for isolation of ribosomal protein genes. These genes will be isolated by conventional cDNA cloning. In addition, DNA-mediated gene transfer and plasmid rescue techniques will be used to isolate specific ribosomal protein genes from mutant cells resistant to drugs which interact with the ribosome. In the course of this work, we will optimize, for mosquito cells, gene transfer protocols. This work will provide basic information on the biochemistry and physiology of the mosquito, a disease vector of considerable economic importance.